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<head><meta charset="utf-8"><title>rfc/spec updates · t-compiler/wg-nll · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/index.html">t-compiler/wg-nll</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html">rfc/spec updates</a></h3>

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<a name="133954633"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133954633" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133954633">(Sep 14 2018 at 14:06)</a>:</h4>
<blockquote>
<p>I think we ought to revisit the NLL RFC</p>
</blockquote>
<p>I'm a <em>big</em> fan of this kind of thing happening. I think just a new section at the end of the RFC with "differences between the RFC and the real world" would be sufficient. The reference should be the ultimate authority, but it is rarely touched. I think that it's too scary for most people to edit (once it's in there, it's THE FINAL WORD, oh noes), so people read the RFC to figure out things.</p>



<a name="133954761"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133954761" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133954761">(Sep 14 2018 at 14:08)</a>:</h4>
<p>And of course, this stuff also gets "documented" in GitHub, Stack Overflow, URLO/IRLO, Reddit, etc., but that's not great either.</p>



<a name="133955240"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133955240" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133955240">(Sep 14 2018 at 14:15)</a>:</h4>
<p>(context: <a href="#narrow/stream/122657-wg-nll/subject/making.20plans/near/133735334" title="#narrow/stream/122657-wg-nll/subject/making.20plans/near/133735334">https://rust-lang.zulipchat.com/#narrow/stream/122657-wg-nll/subject/making.20plans/near/133735334</a> )</p>



<a name="133955326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133955326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133955326">(Sep 14 2018 at 14:16)</a>:</h4>
<p>Ah yes, sorry. I assumed that quoting would do that for me (I'm catching up on ~2 weeks of backlog <span class="emoji emoji-1f609" title="wink">:wink:</span> )</p>



<a name="133955509"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133955509" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133955509">(Sep 14 2018 at 14:19)</a>:</h4>
<p>unfortunately that's one place where Zulip misses out (the fact that the "quote" command does not actually hyperlink when it could)</p>



<a name="133955522"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133955522" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> pnkfelix <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133955522">(Sep 14 2018 at 14:19)</a>:</h4>
<p>/me wonders whether this could be worth filing an issue in Zulip's github</p>



<a name="133957191"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957191" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957191">(Sep 14 2018 at 14:42)</a>:</h4>
<p>I think the problem with the reference is that we've historically not "vetted" its contents</p>



<a name="133957194"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957194" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957194">(Sep 14 2018 at 14:42)</a>:</h4>
<p>I'm sure it's accurate etc</p>



<a name="133957198"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957198" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957198">(Sep 14 2018 at 14:43)</a>:</h4>
<p>I would like for 2019 to start an effort to change that</p>



<a name="133957210"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957210" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957210">(Sep 14 2018 at 14:43)</a>:</h4>
<p>I know that <span class="user-mention" data-user-id="123893">@alercah</span> and @havvy have done awesome work here anyway</p>



<a name="133957226"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957226" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957226">(Sep 14 2018 at 14:43)</a>:</h4>
<p>tl;dr I think we should put this text into the reference, but we can also have a summary+link in the RFC</p>



<a name="133957238"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957238" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957238">(Sep 14 2018 at 14:43)</a>:</h4>
<p>well, I'm not sure if that's my total feels</p>



<a name="133957248"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957248" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957248">(Sep 14 2018 at 14:43)</a>:</h4>
<p>I had some thoughts about the best process here ...</p>



<a name="133957301"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133957301" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133957301">(Sep 14 2018 at 14:44)</a>:</h4>
<p>...I think I may have talked about them in that post on a propsoed new RFC process</p>



<a name="133959751"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959751" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959751">(Sep 14 2018 at 15:16)</a>:</h4>
<blockquote>
<p>I'm sure it's accurate etc</p>
</blockquote>
<p>DYM "I'm <em>not</em> sure"?</p>



<a name="133959859"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959859" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959859">(Sep 14 2018 at 15:17)</a>:</h4>
<p>I'd also think that the reference could stand to have some styling thing that outlines a section as non-normative / non-binding / non-vetted whatever</p>



<a name="133959935"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959935" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959935">(Sep 14 2018 at 15:18)</a>:</h4>
<blockquote>
<p>DYM "I'm <em>not</em> sure"?</p>
</blockquote>
<p>what I really meant was "I'm sure it's 99% fine"</p>



<a name="133959945"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959945" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959945">(Sep 14 2018 at 15:18)</a>:</h4>
<p>but I also think</p>



<a name="133959953"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959953" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959953">(Sep 14 2018 at 15:18)</a>:</h4>
<p>there is no such thing as a normative spec :)</p>



<a name="133959962"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959962" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959962">(Sep 14 2018 at 15:18)</a>:</h4>
<p>like, spec bugs are a thing</p>



<a name="133959997"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959997" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959997">(Sep 14 2018 at 15:19)</a>:</h4>
<p>certainly.</p>



<a name="133959999"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133959999" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133959999">(Sep 14 2018 at 15:19)</a>:</h4>
<p>what I really mean is: I think there are attempts at normative specs ,but ultimately, when you find a discrepancy between a spec + an impl, it's a time to do inquiry and figure out what the story should be...</p>



<a name="133960013"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960013" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960013">(Sep 14 2018 at 15:19)</a>:</h4>
<p>(of course the longer the spec has been around etc the more normative it is... it's a spectrum)</p>



<a name="133960018"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960018" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jake Goulding <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960018">(Sep 14 2018 at 15:19)</a>:</h4>
<p>metadata on every sentence (word?) with a "confidence percentage" <span class="emoji emoji-1f609" title="wink">:wink:</span></p>



<a name="133960034"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960034" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960034">(Sep 14 2018 at 15:19)</a>:</h4>
<p>tl;dr  think we can just say "This is the spec. Let us know if you find a discrepancy. :)"</p>



<a name="133960091"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960091" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960091">(Sep 14 2018 at 15:20)</a>:</h4>
<p>but I think we should also start and maintain an effort to write tetsts against the spec</p>



<a name="133960099"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960099" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960099">(Sep 14 2018 at 15:20)</a>:</h4>
<p>and proactively find such discrepancies</p>



<a name="133960108"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960108" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960108">(Sep 14 2018 at 15:20)</a>:</h4>
<p>plus fill it out in places where it is lacking</p>



<a name="133960122"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960122" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960122">(Sep 14 2018 at 15:20)</a>:</h4>
<p>some things (e.g., formalizing every detail of typeck) are very hard, we should not start there</p>



<a name="133960142"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/122657-t-compiler/wg-nll/topic/rfc/spec%20updates/near/133960142" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> nikomatsakis <a href="https://rust-lang.github.io/zulip_archive/stream/122657-t-compiler/wg-nll/topic/rfc.2Fspec.20updates.html#133960142">(Sep 14 2018 at 15:20)</a>:</h4>
<p>anyway I know that there's been awesome work done here and I am sad that I haven't <em>really</em> reviewied it in depth</p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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